In the current 3rd Generation Partnership Project (3GPP) long term evolution (LTE) time division duplex (TDD)-Advanced systems, the same frequency bands are used for the uplink and downlink transmissions between enhanced node Bs (eNodeBs) and user equipment (UE). Uplink and downlink transmissions are separated by transmitting either uplink data or downlink data at each pre-determined block of time, known as subframes, on the same frequency bands. In TDD deployment, the uplink and downlink transmissions are structured into radio frames, each 10 ms in time length. Each radio frame may comprise a single frame or two half-frames of each 5 ms in time length. Each half-frame, in turn, may comprise five subframes of 1 ms time length each. Particular designations of subframes within a radio frame for uplink or downlink transmission—referred to as uplink and downlink configurations—can be defined. The seven supported uplink and downlink configurations (also referred to UL/DL configurations, uplink-downlink configurations, or uplink-downlink ratio configurations) are shown in a table 100 of FIG. 1, in which “D” denotes a subframe reserved for downlink transmission, “U” denotes a subframe reserved for uplink transmission, and “S” denotes a special subframe which includes the downlink pilot time slot (DwPTS), guard period (GP) and uplink pilot time slot (UpPTS) fields. Note, among other things, that some configurations have more uplink subframes than other configurations. For example, Configuration 0 has six uplink subframes while Configuration 2 has two uplink subframes.
Once the evolved universal terrestrial radio access network (EUTRAN) decides which one of the above uplink-downlink configurations applies for a given enhanced Node B (eNB or eNodeB), this configuration is not changed during normal operation of the cell or cells served by the eNodeB. This is the case even when uplink or downlink transmission loads are mismatched to the current uplink-downlink configuration. Current 3GPP LTE-Advanced systems do not support flexible adjustment of the uplink and downlink ratio configurations for eNodeBs.